The shipping industry and navies around the world are interested in upgrading ships using advanced technologies to provide, for example, improved fuel efficiency, greater electric capacity, and more sophisticated onboard systems. Size and weight reductions in propulsion and power generation systems will provide additional room for more equipment, cargo, and/or crew, as well as improved fuel economy. For naval ships, new varieties of electric weapons, advanced sensors, and integrated support systems may be of interest to navies around the world. Such systems may include electromagnetic guns and high-powered laser or microwave directed-energy weapons, which present especially rigorous electrical power demands. For example, they require large amounts of electrical power over very short time periods of time.
Typical ship propulsion and energy generation systems utilize marine gas turbine and diesel engine technologies to drive the ships propeller shafts through a main reduction gear for mobility and separate dedicated electric power generated by prime movers are used to drive electrical generators to power electrical grids which feed the onboard electrical systems. There are physical limits in size and weight reductions that can be achieved with gas turbine technologies and significant advancements are not likely. In addition, marine gas turbine and diesel engine generator technologies, which are used to produce electrical power are typically designed to operate efficiently and reliably at constant loading. Therefore, they are unable to support the above described dynamic loads associated with advanced electrical systems, such as electric weapons, without significant and costly electrical system upgrades which may not even fit on the ship. For example, with a conventional gas turbine generator system an additional energy storage system, such as batteries or a fly wheel, may be needed to eliminate the pulse effects of the primary energy storage powering the electric weapons.
The concept of an all-electric ship, which may include the use of electrical means for all power needs, including propulsion, in lieu of other means such as mechanical, pneumatic, and hydraulic, is gaining momentum. Such all-electric ships, having an integrated power system (IPS), in particular those utilizing high temperature superconductor motors and generators, will result in size and weight reductions, which will provide additional room and weight capacity for more equipment, cargo, weapons, and/or crew, as well as improved efficiency and fuel economy. These systems are envisioned to share electric power seamlessly across a common electric bus allowing for universally shared power for all electric functions of the ship from powering the propellers, to energizing the combat systems, to feeding the lighting loads. However, many current ship designs are such that there is not sufficient space or weight capacity available to support the amount of additional power needed and, even if there were, the power system is not sufficiently developed to manage and smooth out the extreme pulse power distortions that are a byproduct of electric weapons for a “common electric bus” architecture design to operate and survive. Thus, the true all-electric solution is not currently a viable option for many space and weight constrained ships.
Therefore, there exists a need for a cost effective ship propulsion and energy system which is capable of powering new varieties of weapons, advanced sensors, and integrated support systems having rigorous power demands and for such a system which can provide size and weight reductions to deliver more space and improved fuel economy.